1. Field of the Invention
The invention relates to chain stitch sewing machines.
2. Description of the Prior Art
Single thread chain switch sewing machines with pivoted thread seizing loopers are commonly used for sewing buttons onto garments and for hemming or tacking. Such a machine may be seem, for example, in U.S. Pat. No. 4,411,210 of Karl H. Killinger for "Actuating Mechanism for a Double Pointed Looper in a Sewing Machine", issued Oct. 25, 1983.
A machined described in said patent includes a povitably mounted cam having a looper affixed thereto, and spring means which biases the looper cam assembly axially to a position wherein tracks in the cam are disposed for engagement with a cam actuator, and a gate for controlling access to the cam tracks is disposed for engagement with a gate regulating spring. During operation of the machine, the looper is pivoted to bring looper points into cooperation with a sewing needle and so provide for the formation of chain stitches. However, faulty operation of the machine is sometimes experienced due to engagement of the needle with a looper point resulting in axial movement of the looper cam assembly and disengagement of the cam from the actuator and/or the gate from the gate spring.
It is a prime object of the present invention to provide an improved chain stitch sewing machine in which the operation is unaffected by engagement of a sewing needle with a looper point.
It is another object of the invention to provide a chain stitch sewing machine with a pivotably mounted looper and cam assembly on which the looper can be deflected away from the cam without affecting the axial position of the cam in the machine.
Other objects and advantages of the invention will become apparent during a reading of the specification taken in connection with the accompanying drawings.